UJOR Fuel Tank - Fuel Gauge Calibration

[Bluvan]

Been rolling around with the first production UJOR fuel tank for a while now. I am sharing my findings on how the stock fuel gauge corresponds with this tank.

In the first 100 miles the gauge does not move off full. In the next 250 miles the gauge cycles from full to empty and the light comes on. Filling it at this point gets 29 gallons in the tank. So I am assuming there is about 8-10 gallons sitting in the tank when the light comes on.

These findings are on a 2003 7.3 so others may behave differently. This is also my first custom fuel tank experience. If you have one of these tanks in service please share your results and with enough results we can build some confidence into how far past empty these can be pushed. I am thinking another 100 miles...

Any insight into how far off the bottom the fuel pick up sits and how much pump fuel goes in a dry tank would also help. Also any thoughts on how much fuel is in the stock tank when the light comes on could help as well.

This is not a milage thread but for those doing the math my mileage is a little low as most of the miles are around town, driving in the nor cal mountains, learning to drive with the dp tuner 80 hp econo tune, or simply speeding.

 

[ujoint]

The tank is the same depth as the factory tank, so the sending unit reads correctly. The new tank is wider and longer, so yes, when it hits E there is quite a bit left.

 

[BajaSportsmobile]

The tank is the same depth as the factory tank, so the sending unit reads correctly. The new tank is wider and longer, so yes, when it hits E there is quite a bit left.

This is the same thing all major replacement tanks do - same depth, different volume, so more volume left at any point on the gauge. I've installed a few Transfer Flow tanks in F250/350s and get the same result. I think that it does not take much to throw the sender off a little while handling it.

I'm impressed with Chris' work and products - true innovator in this market segment. Nice new products coming out all the time.

 

[derjack]

It has actually nothing to do with Ujoint´s tank. The problem is the indicator that gives the volume info to the gauge. These can be configured in a way. It´s electronic stuff. The beginning and the end of the indicator must fit to the tank (I guess it´s actually the hight of the tank itself).

This is what I mean, Wikipedia:
Today, tanks carry a float tube with a plastic float, whose vertical height stand changed an electrical resistance. This resistance is measured by the indicator and the corresponding level shown, mostly in the present instrument. A common standard size is 240-33 ohm, 240 full and 33 when the tank is empty. In addition to these passive tank donors, there are also active tank dealer who spend a variable voltage.